Thyroxine (T4) is a thyroid hormone that helps regulate metabolism. The thyroid T4 blood test helps evaluate T4 levels in your blood, hence determining if your thyroid is working properly.

Reasons for Testing T4

A T4 blood test is commonly done to:

• Identify symptoms that may suggest a thyroid issue
• Gain a detailed understanding of thyroid function and overall health
• Evaluate the effectiveness of thyroid medication

Preparing for Your T4 Blood Test

• Take plenty of water 24 hours before your test to make the blood extraction easier.
• Put on loose-fitting clothes that allow easy access to your arms and hands.
• If you are taking anticoagulants, it’s best to take them after your test. If that’s not possible, only take them beforehand if necessary.
• If you feel anxious about needles, inform your healthcare team so that they will help you stay relaxed and ensure a smooth, quick procedure.